Field of the Invention
The present invention relates to an image sensor and an image capturing apparatus, and especially to a configuration of an image sensor.
Description of the Related Art
Conventionally, CMOS image sensors and similar image sensors are widely used in image capturing apparatuses, such as digital still cameras and digital video cameras.
In recent years, image sensors in which an image sensor substrate and a signal processor substrate are stacked together have been suggested; the image sensor substrate is composed of a plurality of pixels including photoelectric converters that convert light into electricity, and the signal processor substrate applies signal processing to image pickup signals output from the image sensor substrate. Japanese Patent Laid-Open No. 2015-41971 suggests, as one example of such image sensors, an image sensor having a signal processor substrate that converts analog signals output from an image sensor substrate into digital signals, and then compresses the digital signals. Image sensors with a stacked structure can include a smaller and more functional signal processor substrate.
There is a great need for application of processing to an image (a RAW image) that has been output from an image capturing apparatus and stored to a recording medium, e.g., additional image processing (defective pixel correction, noise reduction, etc.) and redevelopment with a different white balance.
However, in order to apply image processing and redeveloping processing to an image (a RAW image) that has been output from an image sensor, an image processing chip needs to be provided outside the image sensor.
Furthermore, as described in Japanese Patent Laid-Open No. 2015-41971, in applying image processing and developing processing to compressed image data that has been output to the outside of an image sensor, the compressed image data needs to be restored to uncompressed image data through decompression processing.